Double-walled resin container and method for producing same

Abstract

A double-walled resin container includes: an outer container made of resin and having a tapered shape in which an upper surface is opened, a bottom surface is closed, and a diameter is reduced from an upper surface side to a bottom surface side; and an inner container made of resin and inserted into the outer container from the upper surface side, the double-walled resin container including a heat insulating space in a gap between the outer container and the inner container. The outer container and the inner container are each formed by a biaxial stretch blow method.

1 . A double-walled resin container comprising:
 an outer container made of resin and having a tapered shape in which an upper surface is opened, a bottom surface is closed, and a diameter is reduced from an upper surface side to a bottom surface side; and   an inner container made of resin and inserted into the outer container from the upper surface side,   the double-walled resin container including a heat insulating space in a gap between the outer container and the inner container, wherein   the outer container and the inner container are each molded by a biaxial stretch blow method.   
     
     
         2 . The double-walled resin container according to  claim 1 , wherein
 one of the outer container and the inner container has an engagement protrusion extending in a circumferential direction, and   an other of the outer container and the inner container has an engagement groove extending in the circumferential direction and engaging with the engagement protrusion.   
     
     
         3 . The double-walled resin container according to  claim 1 , wherein
 at least one of the outer container and the inner container includes a spacer portion that protrudes toward an other container and holds the heat insulating space.   
     
     
         4 . The double-walled resin container according to  claim 1 , wherein
 the inner container includes, at an upper end, a flange portion having an annular shape and projecting radially outward, and   an upper end of the outer container contacts a lower surface of the flange portion.   
     
     
         5 . A method for manufacturing a double-walled resin container that is formed by overlapping an outer container and an inner container, which are both made of resin, and includes a heat insulating space in a gap between the outer container and the inner container, the method comprising:
 molding, by a biaxial stretch blow method, the outer container that has a tapered shape in which an upper surface is opened, a bottom surface is closed, and a diameter is reduced from an upper surface side to a bottom surface side, from a preform made of resin;   molding the inner container from a preform made of resin by the biaxial stretch blow method; and   inserting the inner container from the upper surface side of the outer container to assemble the double-walled resin container.